Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5426438 | Surface Science | 2006 | 5 Pages |
The c(5â2 Ã â2)R45°-Pb/Cu(1 0 0) surface phase is investigated by means of angle resolved ultraviolet photoemission and low energy electron diffraction in the temperature range between 300 and 550 K. We identify and characterize a temperature-induced surface phase transition at 440 K from the room temperature c(5â2 Ã â2) R45° phase to a (â2 Ã â2)R45° structure with split superstructure spots. The phase transition is fully reversible and takes place before the two-dimensional melting of the structure at 520 K. The electronic structure of the split (â2 Ã â2)R45° phase is characterized by a metallic free-electron like surface band. This surface band is backfolded with c(5â2 Ã â2)R45° periodicity phase at room temperature, giving rise to a surface band gap at the Fermi energy. We propose that a gain in electronic energy explains in part the stability of the c(5â2 Ã â2)R45° phase.